Journal of Hydrogen, Fuel Cell and Energy Storage
Volume:10 Issue: 3, Summer 2023

Recently, the use of clean energy has become the interest topic for researchers. Hydrogen has attracted the attention of researchers and industries as an alternative energy. Among the sources that exist for hydrogen production, methanol fuel is considered as an attractive feedstock for hydrogen production due to its advantages. The output stream from the methanol steam reforming reactor contains some carbon monoxide, and considering that carbon monoxide leads to fuel cell catalyst damage, its concentration should be reduced. In the present work, the focus is on the design and simulation of the purification system of the methanol steam reforming process. Therefore, in the present study, in order to reduce the concentration of carbon monoxide output of the reformer, the PROX unit was used. In this system, Pt/Al2O3 catalyst was used to increase the reaction rate. Aspen plus V11.0 software was used to simulate the PROX system. The results showed that carbon monoxide was completely removed from the system during the reactor. Next, in order to increase the concentration of hydrogen, the PSA column including activated carbon absorber was used as a purification system. Simulation and design of PSA process were done in Aspen adsorption V11.0 software. Hydrogen purity of 99.9915% was obtained in the output stream from the PSA column. To validation of the results obtained from the simulation, the present work was compared with the study of Abdeljaoued and et al [30]. The results obtained from the simulation showed the acceptable error percentage with the results of the article.

The increase in demand for high voltage boost features such as solar cells and fuel cells has increased the inefficiency of the traditional boost circuit due to the high duty ratio. In this paper, to supply the output voltage of renewable energy sources and overcome their low voltage, a highly boosted interleaved sepic converter without coupled inductor is proposed. The proposed converter has various advantages, which can be mentioned in reducing the voltage on the converter switch and providing switching conditions at zero current for switches and diodes. Also, the implementation of the control circuit is simple, and the input current ripple of the converter is very low. The analysis and relationships of the converter design are stated, and it is simulated in the PSPICE software. To check the correctness of the design, a sample of the converter has been implemented in the laboratory. The results of the laboratory sample confirm the theoretical analysis of the converter.

Water management is essential because of its effect on the performance and durability of the polymer electrolyte membrane (PEM) fuel cells. This paper studies the flow in the cathode gas diffusion layer (GDL) of a PEM fuel cell using a non-isothermal two-phase model. For this purpose, the conservation equations of mass, momentum, energy, and other auxiliary equations have been solved numerically and validated with data available in the papers. The results show that the pressure variation of the gas mixture (P_g) along the cathode GDL is negligible, while the capillary pressure (P_c) is significant. An increase in the pressure of the cathode channel as well as the porosity of GDL leads to an increase in the concentration of oxygen in the cathode catalyst layer, but by increasing the porosity coefficient of the electrodes from 0.4 to 0.7, the effective thermal conductivity of the fuel cell decreases and the maximum temperature of the fuel cell increases by about 1K. The flow of liquid water and the consequent saturation are higher in the vicinity of the cathode catalyst layer, but due to evaporation, their amount decreases as approach the channel. In the current density range of 0.6< j< 1A/cm^2, the α parameter (which is defined as the ratio of the water entering from the membrane to the catalyst to the water produced due to the reaction) is nearly equal to 1.2, as a result, the water entering the cathode GDL increases proportionally to the current density.

Among the various fuel cells, Proton Exchange Membrane Fuel Cells (PEMFC) offer many advantages, such as low temperature operation, quick starting, and high energy density. Therefore, the PEMFC can be extensively applied to power generation, portable electric equipment and hybrid vehicles. Heat treatable aluminum alloys such as 7075, because of high strength low density and corrosion resistance, are used widely in industry and PEMFC. In this industry, besides of mechanical properties, corrosion resistance is very important to work at that environment. T6 heat treatment has recommended for this regard, but this temper treatment is sensitive to corrosion induced and Stress Corrosion Cracking (SCC). In this work 5% Pre- Stretching after solution applied to this alloy in order to investigate its resistance to SCC. The results show that by this treatment, the precipitates immigrate from grain boundary into the grains inside and improve Stress Crack Corrosion (SCC) properties which is very important for using in PEMFC. Moreover, the results show that 5% Pre- Stretching after solution improves both tensile strength and elongation and 463MPa Tensile strength with 12% Elongation can be obtained by this heat treatment.

In the present study, combination of a solid oxide fuel cell with two CCP subsystem to generate power and refrigeration is investigated. The proposed system consists of two combined ORC-VCR system which their input energy is supplied by the waste heat of a SOFC. The energy and exergy analysis is carried out for the system components. The results indicate that recovering the waste heat of the SOFC, the energy and exergy efficiencies are improved by 45.82% and 6.14% compared to the standalone SOFC system. Besides, the proposed system can generate 382.4kW power and 176.28kW refrigeration, respectively. Moreover, the exergy analysis demonstrates that the air heat exchanger, afterburner, SOFC stack and evaporatorI have considerable exergy destruction rate in comparison with other system components. The effect of key parameters of the SOFC and ORC-VCR subsystems on the system performance are also analyzed. The results revealed that SOFC net power and refrigeration capacity increase with increasing current density. Furthermore, by increasing the SOFC operating temperature, the refrigeration capacity increases. However, there is an optimum value for the fuel cell operating temperature in which the SOFC net power is maximum.

This review article delves into the intricate mechanical behaviors exhibited by metal hydrides within hydrogen storage tanks during hydrogen absorption and release processes. The metal’s crystal structure undergoes expansion upon hydrogen absorption, leading to the liberation of energy—an exothermic phenomenon. Conversely, during hydrogen release, the metal contracts, necessitating an intake of energy from the surroundings—an endothermic occurrence. These cyclic processes give rise to two significant mechanical implications: firstly, the initiation of a decrepitation mechanism; secondly, the material undergoes rhythmic expansion and contraction, often referred to as "hydride breathing." These dual mechanisms collectively contribute to the escalating strain and stress imposed on the walls of the metal hydride container, thereby impacting its structural integrity. This review delves into the comprehensive landscape of experimental studies, measurement techniques, and modeling approaches employed in analyzing stress and strain within metal hydride hydrogen storage tanks. The report encompasses an exploration of the factors amplifying mechanical stresses within the metal hydride bed, alongside proposed strategies for their mitigation and control. Furthermore, the article concludes by presenting pragmatic and experimental recommendations aimed at the development of secure hydrogen storage tanks grounded in metal hydride technology.